Emergency department (ED) overcrowding has been shown to be widespread, and to affect quality of care in adult populations, although no studies have examined the overcrowding-quality association in a pediatric population. The broad objective of the proposed study is to address this literature gap by examining the association between ED overcrowding and quality-of-care in a pediatric population, using asthma as the disease model. The study population will include all patients aged 2-18 years presenting for acute asthma care at a tertiary care pediatric ED. A database will be constructed from the electronic medical records of our study population, including patient characteristics, symptom severity, overcrowding measures, and two types of quality measures: process measures and outcome measures. Provider characteristics will be derived from the ED providers and linked to the patient database. The primary independent variable will be a composite measure of pediatric ED overcrowding. Other independent variables will include patient characteristics, including asthma severity score, and provider characteristics. Process quality measures will include timeliness of medication administration and ED length-of-stay, and outcome quality measures will include disposition, readmission, use of recommended medications, and discharge education. [unreadable] [unreadable] The first set of analyses will use logistic regression and survival analysis to model the association [unreadable] between ED overcrowding and each of the process and outcome measures of quality, with patient and [unreadable] provider-characteristics as covariates. The second analyses will use the overcrowding-quality [unreadable] models to further test for mediation by process measures and moderation by patient- and provider characteristics variables. [unreadable] [unreadable] [unreadable] Understanding the overcrowding-quality relationship will allow researchers, clinicians, and [unreadable] administrators to better measure, understand and manage those overcrowding-related factors most [unreadable] strongly associated with variations in quality of pediatric care in an ED setting. Demonstration of an [unreadable] association between overcrowding and decreased quality of ED care for children will also present a [unreadable] compelling argument for improved allocation of public funding for ED care. A pediatric model linking [unreadable] ED overcrowding to quality of care can thereby improve the health care system's ability to deliver [unreadable] safe, high quality health care, the second of the Agency for Healthcare Research and Quality's [unreadable] (AHRQ) four priority areas. Because the study centers on a priority population-children-it also [unreadable] addresses the AHRQ mission of assessing the quality of care for vulnerable populations. [unreadable] [unreadable] [unreadable] [unreadable]